Abstract: Fruit juices are rich in various bioactive components such as polyphenols, carotenoids, and vitamin C. During processing, these components are susceptible to oxidative degradation, isomerization, and polymerization due to factors including heat, oxygen, enzymes, and mechanical stress, leading to a decline in the nutritional quality and functional activity. This article systematically elucidates the mechanisms by which key processing units, namely juicing, homogenization, concentration, and sterilization, affect the stability and bioavailability of bioactive components. It highlights that cell wall disruption, matrix interactions, and processing-induced molecular transformations are the core factors regulating nutrient retention and absorption efficiency. Furthermore, the article reviews regulatory strategies based on non-thermal processing (e.g., high-pressure processing, pulsed electric fields, ultrasound), matrix engineering (e.g., the construction of lipid/emulsion systems), and combination of multiple technologies, aiming to achieve efficient component release, structural preservation, and enhanced bioavailability. By integrating mechanistic analysis with technological optimization, this review provides theoretical foundations and technical pathways for the development of nutrition-oriented juice processing systems.

Key words: fruit juice processing; bioactive components; stability; bioavailability; regulatory mechanism